At Coolhotyoga, the instructors teach yoga classes in both hot and cool rooms, of course, but they do much more to help their clients build muscle and burn fat. They also defy science in their anti-gravity yoga series, in which guests strike yoga poses in midair in ceiling-suspended hammocks that support the body while coaxing deeper stretches. On the cardio end of things, they offer both Piloxing—a blend of Pilates and boxing—and booty barre classes—which combine ballet's core-strengthening exercises with light weightlifting, such as picking up the nearest ballerina.